Track-type vehicles are commonly used for moving earth or the like in applications requiring high mobility, for example in road construction or for agricultural purposes. Such track-type vehicles include a continuous flexible (e.g., rubber) track which extends about a plurality of wheels. The track includes an outer surface which engages the ground and an inner surface having lugs (sometimes referred to as drive lugs) which engage the drive wheels, idler wheels and bogey wheels, for example. Use places enormous strain on the mechanics of the track apparatus, particularly with respect to the flexible track and the lugs thereon.
The Achilles heel of flexible tracks for such track-type vehicles is the lug which comes into direct contact with the wheels, usually including a large drive wheel, with all or much of the forces of the track apparatus being exerted on the track lugs. Two particular problems with conventional lugs are side loading and over-torque. With normal wear, the lugs will begin to degrade and be chipped or otherwise worn by virtue of lateral forces applied on the track. Track-driven systems generally resist lateral motion, but such forces (and other forces) are present in normal use of the track apparatus. When a lug wears down, the track wear allows the continuous flexible track to shift laterally. As a result, the track will ride more toward the edges of the lug that have worn down and this will continue to wear down such lug edges.
Another challenge with conventional lugs is finding a balance between strength and flexibility. Improved strength and durability are highly desirable, but where flexibility is sacrificed the useful life of the lugs is severely limited. The lugs need to be durable, but also need to have the flexibility to allow them to bend or flex around the smaller radii of the smaller (typically lower) wheels.
Because the lugs are susceptible to mechanical damage, side loading and over-torque, there is a need for an improved lug that has enhanced durability without sacrificing highly desirable flexibility. There is also a need for an improved lug with an increased useful life, thereby reducing the need for replacement of a lug, or the entire track. There is a further need for an improved lug that will minimize wear from lateral forces on the belt and thereby increase the useful life of each lug.